The eruption of Rabaul, Papua New Guinea, September, 1994.Photo: Australian Broadcasting Company.

Planning for Disaster

In September 1994, Rabaul volcano on the Papua New Guinean island of New Britain erupted.
"The death toll could have been many thousands, because about 75 percent of the
houses collapsed," said Dr. Stanley Williams, a volcanologist at Arizona State
University who visited the site shortly after the blast. As it turned out, only a
handful of people died.

There are two reasons for this stunning success. First, in the hours leading up the
eruption, observant elders who had survived a 1937 eruption of Rabaul noticed—and acted upon—several strange occurrences that had also preceded that
long-ago blast. According to Ben Talai, assistant director of the Rabaul
Volcano Observatory, these included the ground shaking vertically rather than
horizontally (as it had done periodically since 1983); megapod birds suddenly
abandoning their nests at the base of the volcano; dogs barking continuously and
scratching and sniffing the earth; and sea snakes crawling ashore.

Second, residents followed a carefully designed evacuation plan.

Below are the dramatic particulars of the Rabaul evacuation, as related in
"Reducing Volcanic Risk," a 1997 video produced by the International Association
of Volcanology and Chemistry of the Earth's Interior (IAVCEI) and the United
Nations Educational Scientific and Cultural Organization (UNESCO).
As Stan Williams noted, the evacuation was "a wonderful example of
how people can be educated to save themselves."

The city of Rabaul and its harbor are located in the middle of an enormous
volcanic crater. Just before and during World War II, explosive eruptions built
[a large] cone along the harbor and caused a series of ash flows, tsunamis, and
extremely heavy ash fall. The eruptions killed 500 people.

Beginning in 1983, the volcano threatened to erupt again. Scientists
monitoring Rabaul's crater detected a dramatic increase in earthquake activity
that continued for the next 11 years. Tens of thousands of earthquakes rattled
the harbor. Scientists also detected other changes caused by magma moving
below. Parts of the bay were pushed up by more than a yard. Even so, no
eruption took place. But the volcano's warning signs were enough for the people
of Rabaul to put into place the three components of an emergency plan:

Educating the people of Rabaul about the evacuation plan.

People were informed of the hazards they faced if the volcano actually
erupted. Scientists and community leaders gave dozens of presentations to
describe the effects of different types of eruptions that were likely to occur.
Maps of hazardous areas were posted throughout the region. If officials should
ever order an evacuation ... people would know how to get to safe areas, and
they would know the location of help stations along the way.

As a way to announce warnings clearly, the emergency plan defined four
stages of alert that were determined by the intensity of the volcano's
activity. For each stage of alert, the plan identified the type of warning that
would be announced to the public and how it would be done. As soon as
scientists determined that the volcano's activity had reached a new level, the
next stage of alert was to be announced, eventually leading to an evacuation.

Finally, everyone practiced evacuating the hazard areas to ensure that
people would know where to go, what to bring, and how best to mobilize their
community resources in an emergency.

Despite all these preparations, no one could foresee how well the plan would
work when the real test finally came on September 18, 1994. On that Sunday
morning, two large earthquakes were felt around Rabaul. Earthquake activity
suddenly increased later in the day, and by late evening, parts of the
shoreline began to rise noticeably.

Evacuation of Rabaul.

Knowing what this activity meant, people throughout the area began moving to
the safe areas on their own, even though an official evacuation had not yet
been declared. With help from emergency response workers, the spontaneous
evacuation of 30,000 people continued through the night and into the early
morning. As the last people were leaving the hazardous areas, volcanoes on both
sides of the harbor began erupting.

While the city was severely damaged by ash fall in the coming weeks, only
three people died during the evacuation—a tribute to the emergency plan that
was prepared and practiced a decade earlier.

Are you and your community ready for a volcanic eruption? Do you know which
areas will be dangerous during the next eruption? Do you have an emergency
plan? And when faced with scientific uncertainty as to the size and timing of
an eruption, are you willing to err on the side of safety and accept the
possibility of false alarms? The ultimate test of your emergency preparation is
a real eruption. The time to reduce your volcanic risk is now, before your
volcano threatens to erupt. And then, when your volcano rumbles back to life,
don't hesitate to use your emergency plan.